A valve near the top of my water heater is leaking into a drain line

Q: A valve near the top of my water heater is leaking into a drain line. When I flip the trigger I can open the flow further but I can’t get it to close completely. What is wrong?

A: Both gas and electric water heaters have a safety device called a pressure relief valve. In case the tank over-pressurizes, the relief valve opens to release pressure. If the valve doesn’t open correctly, the tank can over-pressurize and explode. However, the valve should not remain open at all times. Sometimes debris in the water supply can lodge in the valve and prevent closure. With the water supply completely open, trigger the relief valve to open the flow and blast away any potential blockage. If this doesn’t work after a few attempts, the valve has probably gone bad and requires replacement.